Thunderbird uses wrong encoding (ISO 8859-1 instead of UTF-8) for SMTP AUTH PLAIN



MailNews Core
Networking: SMTP
5 years ago
2 years ago


(Reporter: S, Unassigned)


Windows 7

Firefox Tracking Flags

(Not tracked)




5 years ago
User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.22 (KHTML, like Gecko) Chrome/25.0.1364.97 Safari/537.22

Steps to reproduce:

I used Thunderbird on MS Windows for SMTP AUTH login using PLAIN with a username containing the German umlaut "ü". When I 'm replacing the umlaut with "ü" the login is possible.

Actual results:

The login failed.

Expected results:

The login should be possible.

According to RFC 4616 the message is encoded using UTF-8. I think Thunderbird is encoding the login string with base64 based on ISO-8859-1 encoded string instead of a UTF-8 encoded string.

Comment 1

5 years ago
Are you indeed using Thunderbird 3.1 as the version stated when you opened this bug? (moving it to MailNews Core makes it the respective Gecko version.)
Component: Untriaged → Networking: SMTP
Product: Thunderbird → MailNews Core
Version: 3.1 → 1.9.2 Branch

Comment 2

5 years ago
Hmm, the built-in log omits the username during authentication. Do you have a log somewhere showing the encoding of the username?

Comment 3

5 years ago
I tested it with the current Thunderbird version. In the reject.log of my local Exim the umlaut "ü" in the wrong login is logged as "\374". Exim is logging non-ascii characters in octal form.

Comment 4

5 years ago
That's 0xFC in hex and thus matches "ü" in the ISO 8859-1 table.
Thus, it's definitely not UTF-8 what is sent...


5 years ago
Summary: Thunderbird uses wrong encoding for SMTP AUTH PLAIN → Thunderbird uses wrong encoding (ISO 8859-1 instead of UTF-8) for SMTP AUTH PLAIN


5 years ago
Version: 1.9.2 Branch → 17

Comment 5

5 years ago
I suppose that should be here:

Something there not liking utf-8?
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